Will this mirror cell mod deform my images?

[John K]

Hi guys,

I have a 12.5" f/5 full thickness (2") Newtonian mirror mounted on a threaded 3 point push/pull mirror cell which over the years has developed some movement in the threaded cusps which are attached to the bottom of my mirror with black silicone.

Rather than take apart and re-build the mirror cell, I was hoping to simply insert some springs and additional round disk cusps inside the mirror cell and simply push the mirror upwards and away from the siliconed attachment points thus removing the slop that I am experiencing.

This would be similar to having springs built into the push/pull threaded rods but would work in isolation and counteract the current attachment points.

It's a quick and easy fix - but my only concern is if this is likely to deform my images.

See attached image with one spring and round disk/cusp inserted which works in terms of removing the slop on that side of the mirror cell.

Look forward to comments.

John K.

[Shiraz]

it's a good thick mirror John, but I still reckon you would still be asking for trouble with push/pull mounting.

Is there any way that you could put the springs over the main bolts to tighten the cups onto the bolt heads and take out any slack in the threads? Do you think that would help?

[John K]

Thanks Ray - Was thinking the same but it's a hassle to take it all apart to make that happen - that's the ideal but a hassle.